Cownose Rays Return

Scientists refute their reputation as oyster bandits

By Kathy Knotts

The rays are back. Anglers and paddlers are already spotting schools — sometimes called fevers — of cownose rays in Bay waters.
Perhaps this year they will be met with a warmer welcome than in years past thanks to a long-awaited acquittal for their impacts on wild oyster populations.
These gentle gliders migrate up the Bay in May to give birth to their pups. They generally stay till October. A decade ago, cownose rays in the Atlantic were accused of gorging on oysters in the Bay at the time oyster populations were crashing. The rays became the villains.
An ensuing campaign to “Save the Bay, Eat a Ray” encouraged ray fishing tournaments as well as creative efforts to promote cownose ray as a table fish. New research has cleared the big flappers of many charges of villainy.
Rays eat oysters — as we do — when they can get them.
“Both oyster restoration and aquaculture efforts placed large numbers of small single oysters out where rays could eat them like popcorn,” explains Smithsonian Environment Research Center scientist Matt Ogburn. “By modifying how oysters are planted on shellfish beds (i.e., oyster spat set on shell), predation has been minimized.”
The historic decline of oysters in the Bay seems to have more to do with excessive harvesting and pollution than with rays.
To get better answers, scientists are studying the creatures and have recorded the first full annual migration of a Chesapeake cownose ray.
“We don’t know exactly what ecological role cownose rays play in the Bay,” says Simon Brown, biologist with Maryland’s Department of Natural Resources.
“But we know that the Chesapeake Bay plays a huge role as the place where they come to give birth and mate, and we know that rays have always been here. Stingray Point is named for where Captain John Smith was stung by a ray,” Brown says. “I know they can be a nuisance to both watermen and restoration projects, but a restored Bay should be resilient enough to support both vibrant fisheries and the Bay’s native creatures.”